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package org.netbeans.api.javafx.source.support;

import com.sun.javafx.api.tree.JavaFXTreePathScanner;
import com.sun.javafx.api.tree.Tree;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 *
 * @author Jan Lahoda
 */
public class CancellableTreePathScanner<R,P> extends JavaFXTreePathScanner<R,P> {

    private final AtomicBoolean internalCanceled;
    private final AtomicBoolean canceled;

    /**Construct a new CancellableTreePathScanner which can be canceled by calling
     * the {@link #cancel} method.
     */
    public CancellableTreePathScanner() {
        this(null);
    }

    /**Construct a new CancellableTreePath Scanner which can be canceled either by calling
     * the {@link #cancel} method, or by setting <code>true</code> into the provided
     * <code>canceled</code> {@link AtomicBoolean}.
     * 
     * @param canceled an {@link AtomicBoolean} through which this scanner can be canceled.
     *                 The scanner never changes the state of the {@link AtomicBoolean}.
     * @since 0.29
     */
    public CancellableTreePathScanner(AtomicBoolean canceled) {
        this.canceled = canceled;
        
        this.internalCanceled = new AtomicBoolean();
    }

    protected boolean isCanceled() {
        return internalCanceled.get() || (canceled != null && canceled.get());
    }

    public void cancel() {
        internalCanceled.set(true);
    }

    /** @inheritDoc
     */
    public @Override R scan(Tree tree, P p) {
        if (isCanceled())
            return null;
        
        return super.scan(tree, p);
    }

    /** @inheritDoc
     */
    public @Override R scan(Iterable<? extends Tree> trees, P p) {
        if (isCanceled())
            return null;
        
        return super.scan(trees, p);
    }

}
